EVANSVILLE - The Vanderburgh County Prosecutor's Office is seeking to take back a plea agreement offered to murder suspect Megan Mecum in exchange for testifying against two others also charged in the stabbing death of Keith Vaughn.

Deputy Prosecutor Mike Perry said prosecutors believe Mecum gave false testimony in a deposition last week.

Mecum, James Mayhugh and Hubert Mayhugh III are charged with murder for the March 10, 2012, stabbing of Vaughn, 42, who was Mecum's husband. The couple had recently married but were estranged at the time of Vaughn's death.

In January, Mecum agreed to plead guilty to a new charge of conspiracy to commit armed robbery and separate charges related to possessing methamphetamine while in jail.

Prosecutors agreed to dismiss Mecum's murder charge and several other related felonies, but only if she testified truthfully in the other trials.

She was to have been sentenced according to the plea agreement on Thursday and could have received up to 25 years in prison. Instead, prosecutors filed the motion to withdraw the agreement.

On March 13, Mecum was questioned under oath by defense attorneys for James Mayhugh and Hubert Mayhugh III. Perry and Mecum's public defender, Barry Blackard, were also there.

"During this deposition, the defendeant gave testimony that contradicted portions of her previous statement to the police, and was in direct contradiction to matters of fact known to (prosecutors), which have been disclosed to the defense," according to the motion.

"The state believes that the defendant has given false testimony in violation of the terms of her plea agreement."

Among the other charges Mecum could face again if the plea agreement is withdrawn are armed robbery, burglary, theft and violating a protective order to stay away from Vaughn.

Blackard said he has objected to the attempt to withdraw Mecum's plea. There will be an April 5 hearing on it in Vanderburgh Superior Court.

In pleading guilty in January, Mecum admitted in court that she conspired with James Mayhugh and Hubert Mayhugh III to rob Vaughn and provided the men with a key to his house at 2032 Kathleen Ave.

According to police, Hubert Mayhugh admitted to a family member that he "poked" Vaughn in the neck after Vaughn attempted to stab James Mayhugh during a confrontation inside Vaughn's home during the robbery attempt.

The pair then fled the home with $80 and Vaughn bled to death, according to the Vanderburgh County coroner.

Hubert Mayhugh is scheduled to stand trial for murder in Vanderburgh Circuit Court on April 22. James Mayhugh's trial for murder is scheduled for Aug. 19 in Circuit Court.

Mecum's drug charges stem from a guard's discovery of two bags containing small amounts of the drug underneath her cell mattress in the Vanderburgh County Jail, according to court records.